Many drugs and chemical agents are known to be effective in treatment of diseases. However, such agents also often have deleterious side effects when introduced into the organism in sufficient dosage to treat the targeted tissue.
One attempt to selectively treat diseased tissue is development of chemical agents which selectively affect only the diseased tissue. However, such chemical agents typically are only partially selective for the diseased tissue and often have a deleterious effect on healthy cells. Another attempt to selectively treat diseased tissue is to inject the chemical agent directly into the diseased tissue mass. However, the effect of chemical agents on diseased tissue is often dependent upon delivery of the chemical agent across cell membranes of the cells in the tissue mass as opposed to simply injecting the chemical agent into the tissue. Further, chemical agents which are injected into diseased tissue typically enter the bloodstream and are transported away from the targeted tissue mass before they have a significant therapeutic effect on the tissue mass into which they were injected.
In addition, some diseases and many injuries require very rapid and controlled responses of medication dosage to effectively suppress deleterious effects and symptoms. For example, the blood glucose level of diabetics is subject to rapid and wide fluctuation which can only be dampened by selective injections of insulin. Similarly, patients who have sustained serious injury, such as burn victims, require large doses of pain-relief medication. However, indiscriminant use of powerful analgesics can cause dangerous side-effects or even death.
In both of these examples, current methods are slow to respond to the conditions, or stimuli, which prompt treatment. With respect to diabetes, patients must independently measure blood glucose level if there is doubt as to whether an insulin injection is appropriate. Patients who suffer periods of acute pain must wait for oral medication to take effect, or be injected with large doses of potentially harmful drugs.
Therefore, a need exists for a new method for responding to stimuli generated by disease or injury.